Motion in One DimensionSection 1 Preview Section 1 Falling ObjectsFalling Objects Section 2 Extra QuestionsExtra Questions

Motion in One DimensionSection 3 What do you think? Observe a metal ball being dropped from rest. –Describe the motion in words. –Sketch a velocity-time graph for this motion. Observe the same ball being tossed vertically upward and returning to the starting point. –Describe the motion in words. –Sketch a velocity-time graph for this motion.

Motion in One DimensionSection 3 Free Fall Assumes no air resistance Acceleration is constant for the entire fall Acceleration due to gravity (a g or g ) –Has a value of m/s 2 Negative for downward –Roughly equivalent to -22 (mi/h)/s

Motion in One DimensionSection 3 Free Fall For a ball tossed upward, make predictions for the sign of the velocity and acceleration to complete the chart. Velocity (+, -, or zero) Acceleration (+, -, or zero) When halfway up When at the peak When halfway down +- zero- --

Motion in One DimensionSection 3 Click below to watch the Visual Concept. Visual Concept Free Fall

Motion in One DimensionSection 3 Graphing Free Fall Based on your present understanding of free fall, sketch a velocity-time graph for a ball that is tossed upward (assuming no air resistance). –Is it a straight line? –If so, what is the slope? Compare your predictions to the graph to the right.

Motion in One DimensionSection 3 Click below to watch the Visual Concept. Visual Concept Velocity and Acceleration of an Object at its High Point

Motion in One DimensionSection 3 Classroom Practice Problem A ball is thrown straight up into the air at an initial velocity of 25.0 m/s upward. Create a table showing the ball’s position, velocity and acceleration each second for the first 5 s t (s) y (m) v (m/s) a (m/s 2 )

Motion in One DimensionSection 3 Now what do you think? Review the descriptions and graphs you created at the beginning of the presentation. –Do you want to make any modifications? –For the second graph, circle the point representing the highest point of the toss.

Motion in One DimensionSection 3 Preview Multiple Choice Short Response Extended Response

Motion in One DimensionSection 3 Multiple Choice, continued 9. Which of the following statements is true for a ball thrown vertically upward? A. The ball has a negative acceleration on the way up and a positive acceleration on the way down. B. The ball has a positive acceleration on the way up and a negative acceleration on the way down. C. The ball has zero acceleration on the way up and a positive acceleration on the way down. D. The ball has a constant acceleration throughout its flight.

Motion in One DimensionSection 3 Multiple Choice, continued 9. Which of the following statements is true for a ball thrown vertically upward? A. The ball has a negative acceleration on the way up and a positive acceleration on the way down. B. The ball has a positive acceleration on the way up and a negative acceleration on the way down. C. The ball has zero acceleration on the way up and a positive acceleration on the way down. D. The ball has a constant acceleration throughout its flight.

Motion in One DimensionSection 3 Extended Response, continued 15. A ball is thrown vertically upward with a speed of 25.0 m/s from a height of 2.0 m. a. How long does it take the ball to reach its highest point? b. How long is the ball in the air? Show all of your work for these calculations.

Motion in One DimensionSection 3 Extended Response, continued 15. A ball is thrown vertically upward with a speed of 25.0 m/s from a height of 2.0 m. a. How long does it take the ball to reach its highest point? b. How long is the ball in the air? Show all of your work for these calculations. Answers: a s b s